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authorFrederic Weisbecker <fweisbec@gmail.com>2009-06-04 20:48:04 +0200
committerIngo Molnar <mingo@elte.hu>2009-06-04 21:44:53 +0200
commit0f5486b5c71a831a713ce356d8d06822e3c7c379 (patch)
tree4c62fd39d7477ac333a954934cad52d300e5a010
parent62fc44536c14b5787531bac7417580fca54c88b4 (diff)
perf_counter: Sleep before refresh using poll in perf top
perf top is refreshed every delay_secs the thread runs in such loop: while (sleep(delay_secs)) { print_sym_table(); } At the end of print_sym_table(), poll is used without sleep delay to check if we have something from stdin. It means that this check is done only every delay_secs, which can be higher that 2 secs if the user defined a custom refresh rate. We can drop sleep() here and directly use poll to wait between refresh periods, so that the reaction after the user stops perf top after typing "Enter" is immediate and doesn't suffer from the delay_secs latency. Nb: poll doesn't add any overhead that can parasite perf top measures since it sleeps the entire timeout here. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1244141284-7507-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--Documentation/perf_counter/builtin-top.c20
1 files changed, 9 insertions, 11 deletions
diff --git a/Documentation/perf_counter/builtin-top.c b/Documentation/perf_counter/builtin-top.c
index 31c00ba99b1..28cbde4b6e8 100644
--- a/Documentation/perf_counter/builtin-top.c
+++ b/Documentation/perf_counter/builtin-top.c
@@ -204,7 +204,7 @@ static void print_sym_table(void)
list_remove_active_sym(syme);
}
- write(1, CONSOLE_CLEAR, strlen(CONSOLE_CLEAR));
+ puts(CONSOLE_CLEAR);
printf(
"------------------------------------------------------------------------------\n");
@@ -278,23 +278,21 @@ static void print_sym_table(void)
color_fprintf(stdout, color, "%4.1f%%", pcnt);
printf(" - %016llx : %s\n", sym->start, sym->name);
}
-
- {
- struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
-
- if (poll(&stdin_poll, 1, 0) == 1) {
- printf("key pressed - exiting.\n");
- exit(0);
- }
- }
}
static void *display_thread(void *arg)
{
+ struct pollfd stdin_poll = { .fd = 0, .events = POLLIN };
+ int delay_msecs = delay_secs * 1000;
+
printf("PerfTop refresh period: %d seconds\n", delay_secs);
- while (!sleep(delay_secs))
+ do {
print_sym_table();
+ } while (!poll(&stdin_poll, 1, delay_msecs) == 1);
+
+ printf("key pressed - exiting.\n");
+ exit(0);
return NULL;
}